"Okta In meteorology, an okta is a unit of measurement used to describe the amount of cloud cover at any given location such as a weather station. Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast). In addition, in the SYNOP code there is an extra cloud cover indicator '9' indicating that the sky is totally obscured (i.e. hidden from view), usually due to dense fog or heavy snow. When used in weather charts, okta measurements are shown by"
"Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of measurement of the cloud cover. The cloud cover is correlated to the sunshine duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This value is lower (0.56) when considering clouds with an optical depth larger than 2, and higher when"
"such as the Amazon Rainforest and some others are almost always clear such as the Sahara Desert. Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of measurement of the cloud cover. The cloud cover is correlated to the sunshine duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This"
"Overcast Overcast or overcast weather, as defined by the World Meteorological Organization, is the meteorological condition of clouds obscuring at least 95% of the sky. However, the total cloud cover must not be entirely due to obscuring phenomena near the surface, such as fog. Overcast, written as ""OVC"" in the METAR observation, is reported when the cloud cover is observed to equal eight oktas (eighths). An overcast sky may be explicitly identified as thin (mostly transparent), but otherwise is considered opaque, which always constitutes a ceiling in aviation meteorology. Sometimes clouds can be different colors such as black or white,"
"Octant (instrument) The octant, also called reflecting quadrant, is a measuring instrument used primarily in navigation. It is a type of reflecting instrument. The name ""octant"" derives from the Latin ""octans"" meaning ""eighth part of a circle"", because the instrument's arc is one eighth of a circle. ""Reflecting quadrant"" derives from the instrument using mirrors to reflect the path of light to the observer and, in doing so, doubles the angle measured. This allows the instrument to use a one-eighth of a turn to measure a quarter-turn or quadrant. Isaac Newton's reflecting quadrant was invented around 1699. A detailed description"
"Δ18O In geochemistry, paleoclimatology and paleoceanography ""δ""O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (O) and oxygen-16 (O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, O:O data from corals, foraminifera and ice cores are used as a proxy for temperature. The definition is, in ""per mil"" (‰, parts per thousand): where the standard has a known isotopic composition, such as Vienna Standard Mean Ocean Water (VSMOW). The fractionation can arise"
"Octant (plane geometry) In plane geometry, octant is a circular sector obtained by division of the full circle into 8 equal parts, hence the name. It is a sector with the central angle of 45°. Most commonly, octants are seen on the compass rose. Traditionally wind direction is given as one of the 8 octants (N, NE, E, SE, S, SW, W, NW) because that is more precise than merely giving one of the 4 quadrants, and the wind vane typically does not have enough accuracy to bother with more precise indication. The name of the instrument ""octant"" comes from"
"description of the cloud layers and opacities, in eighths (oktas). For example, CU5 would indicate a cumulus layer with opacity."" Cloud coverage is reported by the number of 'oktas' (eighths) of the sky that is occupied by cloud. This is reported as: METARs can be expressed concisely using so-called ""aviation flight categories"", which indicates what classes of flight can operate at each airport by referring to the visibility and ceiling in each METAR. Four categories are used in the U.S.: METAR abbreviations used in the WX section. Remarks section will also include began and end times of the weather events."
"Outside air temperature In aviation terminology, the outside air temperature (OAT) or static air temperature (SAT) refers to the temperature of the air around an aircraft, but unaffected by the passage of the aircraft through it. The outside air temperature is used in many calculations pertaining to flight planning, some of them being takeoff performance, density altitude, cruise performance and go-around performance. In most texts, the abbreviation, ""OAT"" is used. Most performance and flight planning graphs and tables use either degrees Celsius or Fahrenheit or both. The Kelvin scale, however, is used for Mach number calculations. For example, the speed"
"show the key weather elements, including temperature, dew point, wind, cloud cover, air pressure, pressure tendency, and precipitation. Weather maps primarily use the station model to show surface weather conditions, but the model can also show the weather aloft as reported by a weather balloon's radiosonde or a pilot's report. Station model plots use a mixture of metric and Imperial units depending on the map's location and what is being shown. Surface maps in the United States primarily use Imperial units, such as inches, degrees Fahrenheit, and knots. Most of the world, however, uses metric measurements for everything but wind"
"by KNMI (principal investigator Prof. Dr. P. F. Levelt), in close co-operation with NASA and the Finnish Meteorological Institute. Ozone monitoring instrument The ozone monitoring instrument (OMI) is a visual and ultraviolet spectrometer aboard the NASA Aura spacecraft. OMI can distinguish between aerosol types, such as smoke, dust, and sulfates, and can measure cloud pressure and coverage, which provide data to derive tropospheric ozone. OMI follows in the heritage of TOMS, SBUV, GOME, SCIAMACHY, and GOMOS. It is a wide-field-imaging spectrometer with a 114° across-track viewing angle range that provides a 2600 km wide swath, enabling measurements with a daily"
"assumes they can be considered separate layers, oxygen above water, with different characteristic temperatures and opacities. The temperature and opacity of oxygen in the upper atmosphere do not vary much seasonally and are assumed to be constant at 255 K and 0.378, respectively, at the signal frequency. The remaining parameters in the model, the temperature and opacity of water and the fraction of the received power from the sky, are determined through antenna tippings (measurements of the intensity of the sky signal as a function of elevation) at least once per six-hour observing shift, and more frequently if the weather"
"of the cloud layers can also be included, as can more than one layer of cloud. Heights are in hundreds of feet above sea level and are three digits. Abbreviations used in this group are ""CLR"" (clear), ""FEW"" (few), ""SCT"" (scattered), ""BKN"" (broken) and ""OVC"" (overcast). Temperature (/TA) is the air temperature in whole degrees Celsius as a two-digit value, with negative temperatures preceded by a minus (-) sign. In the United States, negative temperatures are preceded by the letter M (M). Wind velocity (/WV) must contain both the wind speed and direction. Direction is reported as a three-digit value"
"is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On the Earth's surface, temperatures usually range ±40 °C (100 °F to −40 °F) annually. Over thousands of years, changes in the Earth's orbit have affected the amount and distribution of solar energy received by the Earth and influence long-term climate Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future"
"the right aligns the values of δO (right scale) with the reported temperature variations from the Vostok ice core (left scale), following Petit et al. (1999). Δ18O In geochemistry, paleoclimatology and paleoceanography ""δ""O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (O) and oxygen-16 (O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, O:O data from corals, foraminifera and ice cores are used as a proxy for temperature. The definition is, in"
"weather thresholds (e.g. conditions change from visual meteorological conditions to instrument meteorological conditions). The basic weather elements observed are: sky condition, visibility, present weather, obstructions to vision, pressure, temperature, dew point, wind direction and speed, precipitation accumulation, and selected significant remarks. The coded observations are issued as METARs and look similar to this: Getting more information on the atmosphere, more frequently, and from more locations is the key to improving forecasts and warnings. Due to the large installation and operating costs associated with ASOS, the stations are widely spaced. Therefore, the Cooperative Observer Program (COOP), a network of approximately 11,000"
"others as well, remains unknown. National Weather Center The National Weather Center (NWC), on the campus of the University of Oklahoma, is a confederation of federal, state, and academic organizations that work together to better understand events that take place in Earth's atmosphere over a wide range of time and space scales. The NWC partners give equal attention to applying that understanding to the development of improved observation, analysis, assimilation, display, and prediction systems. The National Weather Center also has expertise in local and regional climate, numerical modeling, hydrology, and weather radar. Members of the NWC work with a wide"
"at Eureka, Nunavut, in Canada, where the annual average temperature is . Studying how the weather works on other planets has been seen as helpful in understanding how it works on Earth. Weather on other planets follows many of the same physical principles as weather on Earth, but occurs on different scales and in atmospheres having different chemical composition. The Cassini–Huygens mission to Titan discovered clouds formed from methane or ethane which deposit rain composed of liquid methane and other organic compounds. Earth's atmosphere includes six latitudinal circulation zones, three in each hemisphere. In contrast, Jupiter's banded appearance shows many"
"The Oklahoma Mesonet utilizes a variety of meteorological instruments to collect its observations. Observations are collected through a data logger within an enclosure and transmitted back to the National Weather Center for quality assurance, archival, and public dissemination. The following are records measured by the Oklahoma Mesonet since January 1, 1996. The Oklahoma Mesonet produces many products public use. Every five minutes, maps of all of the meteorological variables are updated to show the latest observations. Users can also look at time series plots of a station (called meteograms) over a given period of time. Quality assured data files are"
"Climatology Climatology (from Greek , ""klima"", ""place, zone""; and , ""-logia"") or climate science is the scientific study of climate, scientifically defined as weather conditions averaged over a period of time. This modern field of study is regarded as a branch of the atmospheric sciences and a subfield of physical geography, which is one of the Earth sciences. Climatology now includes aspects of oceanography and biogeochemistry. Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño–Southern Oscillation (ENSO), the Madden–Julian oscillation (MJO), the North Atlantic oscillation (NAO), the Northern Annular"
"a number of static variables that determine climate, including: latitude, altitude, proportion of land to water, and proximity to oceans and mountains. Degree of vegetation coverage affects solar heat absorption, water retention, and rainfall on a regional level. Surface weather observation Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide. They can be taken manually, by a weather observer, by computer through the use of automated weather stations, or in a hybrid scheme using weather observers to augment the otherwise automated weather station. The ICAO defines the"
"Climate Climate is the statistics of weather over long periods of time. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate differs from weather, in that weather only describes the short-term conditions of these variables in a given region. A region's climate is generated by the climate system, which has five components: atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere. The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water"
"operational tropical cyclone analysis and forecasting at the National Hurricane Center include identifying and locating the center of tropical cyclones, estimating its intensity, and wind radii analysis. The scatterometer's ability to record wind speeds at the surface allows meteorologists to determine whether a low pressure area is forming and enhance the ability to predict sudden changes in structure and strength. The first tropical cyclone captured by the SeaWinds instrument was Typhoon Olga in the western Pacific basin. The system was monitored by the satellite from its generation on July 28 to its demise in early August. In 2007, Bill Proenza,"
"Ozone monitoring instrument The ozone monitoring instrument (OMI) is a visual and ultraviolet spectrometer aboard the NASA Aura spacecraft. OMI can distinguish between aerosol types, such as smoke, dust, and sulfates, and can measure cloud pressure and coverage, which provide data to derive tropospheric ozone. OMI follows in the heritage of TOMS, SBUV, GOME, SCIAMACHY, and GOMOS. It is a wide-field-imaging spectrometer with a 114° across-track viewing angle range that provides a 2600 km wide swath, enabling measurements with a daily global coverage. OMI is continuing the TOMS record for total ozone and other atmospheric parameters related to ozone chemistry"
"reporting system in use in the United States differs from the one used by the World Meteorological Organization (WMO) in that wind speeds are delivered in knots (instead of meters per second), water-equivalent precipitation in hundredths of an inch, and altimeter setting in the customary inches of mercury (instead of hectopascals). Furthermore, temperatures are reported in whole degrees Fahrenheit but are converted to Celsius when encoded in METAR reports. Most synoptic observation charts are expressed in SI units, except for the aforementioned wind speeds, which must be converted for the purposes of calculation. Upper-air temperature charts typically use the Celsius"
"Surface weather observation Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide. They can be taken manually, by a weather observer, by computer through the use of automated weather stations, or in a hybrid scheme using weather observers to augment the otherwise automated weather station. The ICAO defines the International Standard Atmosphere (ISA), which is the model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere, and is used to reduce a station pressure to sea level pressure. Airport observations"
"at the summit as part of their ""Liegekur"" (""deckchair cure""). The summit observatory, which is located at an altitude of , is an important scientific measuring station operated by the Institute for Meteorology and Climate Research of Karlsruhe Institute of Technology. Since 1972 it has measured a variety of atmospheric and climatic phenomena, including the levels of ozone, nitric oxide, sulphur dioxide and various hydrocarbons in the atmosphere as well as meteorological data such as the levels of temperature, dew point, relative humidity, pressure, wind, global and direct irradiance. It became part of the World Meteorological Organization's Background Air Pollution"
"Oxygen-18 Oxygen-18 () is a natural, stable isotope of oxygen and one of the environmental isotopes. In ice cores, mainly Arctic and Antarctic, the ratio of to (known as δ) can be used to determine the temperature of precipitation through time. Assuming that atmospheric circulation and elevation has not changed significantly over the poles, the temperature of ice formation can be calculated as equilibrium fractionation between phases of water that is known for different temperatures. Water molecules are also subject to Rayleigh fractionation as atmospheric water moves from the equator poleward which results in progressive depletion of O-18, or lower"
"Oklahoma Mesonet The Oklahoma Mesonet is a network of environmental monitoring stations designed to measure the environment at the size and duration of mesoscale weather events. The phrase ""mesonet"" is a portmanteau of the words mesoscale and network. In meteorology, “mesoscale” refers to weather events that range in size from approximately to and can last from several minutes to several hours. Mesoscale events include thunderstorms, wind gusts, heat bursts, and dry lines. Without densely spaced weather observations, these mesoscale events might go undetected. In addition to surface weather observations, Oklahoma Mesonet stations also include environmental data such as on insolation"
"Orbital forcing Orbital forcing is the effect on climate of slow changes in the tilt of the Earth's axis and shape of the orbit (see Milankovitch cycles). These orbital changes change the total amount of sunlight reaching the Earth by up to 25% at mid-latitudes (from 400 to 500 Wm at latitudes of 60 degrees). In this context, the term ""forcing"" signifies a physical process that affects the Earth's climate. This mechanism is believed to be responsible for the timing of the ice age cycles. A strict application of the Milankovitch theory does not allow the prediction of a ""sudden"""
"helps determine if they are flying through instrument meteorological conditions (IMC), such as foggy or smoky conditions, as well as areas of intense precipitation. Present weather depicted with the station model can include: To left of center in the station model, the temperature and dew point are plotted. Within the United States on surface weather maps, they are still plotted in degrees Fahrenheit. Otherwise, they will be in units of degrees Celsius. This knowledge is important to meteorologists because when this data is plotted on a map, isotherms and isodrosotherms (lines of equal dew point) are easily analyzed, either by"
"Smith, Arkansas (SRX). Steve Piltz is the Meteorologist-In-Charge (MIC) of this office. National Weather Service Tulsa, Oklahoma National Weather Service - Tulsa, Oklahoma (TSA) is a local weather forecast office responsible for monitoring weather conditions for 7 counties in Northwestern Arkansas, and 25 counties in Eastern Oklahoma. The current office in Tulsa maintains a WSR-88D (NEXRAD) radar system, and Advanced Weather Interactive Processing System (AWIPS) that greatly improve forecasting in the region. Tulsa is in charge of weather forecasts, warnings and local statements as well as aviation weather and NOAA Weather Radio broadcasts in its service area. The office operates"
"dB SPL, or 20 µPa. The airtightness of buildings is measured at 50 Pa. The units of atmospheric pressure commonly used in meteorology were formerly the bar, which was close to the average air pressure on Earth, and the millibar. Since the introduction of SI units, meteorologists generally measure pressures in hectopascals (hPa) unit, equal to 100 pascals or 1 millibar. Exceptions include Canada, which use kilopascals (kPa). In many other fields of science, the SI is preferred, which means Pa with a prefix (in multiples of 1000) is preferred. Many countries also use the millibars. In practically all other"